Tabs2 NPEs if passed no children

[AndyMoreland]

Admittedly this is kind of stupid, but Tabs2 NPEs if passed no children. It probably should just do nothing.

    Tabs2.prototype.getInitialSelectedTabId = function () {
        var _a = this.props, defaultSelectedTabId = _a.defaultSelectedTabId, selectedTabId = _a.selectedTabId;
        if (selectedTabId !== undefined) {
            return selectedTabId;
        }
        else if (defaultSelectedTabId !== undefined) {
            return defaultSelectedTabId;
        }
        else {
            // select first tab in absence of user input
            // NOTE: providing an unknown ID will hide the selection
            return this.getTabChildren()[0].props.id;
        }
    };

Note the code line: this.getTabChildren()[0].props.id;. Dies if getTabChildren() is undefined which occurs when there are no children.